Wrapping elongate articles

ABSTRACT

An elongated article is wrapped by forming thereon a winding of a strip of a flexible wrapping material (12) which has a first face (13) carrying first and second portions (13a, 13b) of a coating of an adhesive substance of a per se known kind which without the application of heat adheres strongly only to itself, the second face (15) being free from such adhesive substance, and by turning over a longitudinal edge portion of the strip which includes said first portion (13a) of the coating, as the strip is wound around the article, so as to bring it into face-to-face with the second portion (13b) of the coating on a previously formed turn of the winding.

BACKGROUND OF THE INVENTION

This invention relates to a method of wrapping elongate articles such aspipes, rods, tubes and the like elements, which may be substantiallystraight through-out their length, or of curved or other non-linearform, or even in the form of a closed loop (for example a coil of wire),such elements being wrapped either singularly or in bundles, and theterm "elongate article" as used herein is intended to encompass bothsuch elements singly and bundles of such elements.

Conventionally, such articles are wrapped by means of one or morelengths of paper or the like which are wound helically around them usingappropriate machinery, for example as shown in German Patentspecification No. 2256708, so that adjacent windings overlap somewhat.In many cases such articles are relatively flexible, due often to theirlength, which may be some 6 or 7 meters for example. As a result flexingof the package gives rise to a tendency for adjacent turns of thewrapping to separate, thereby exposing the article to potential damage.To reduce this tendency it is often desirable for the adjacent windingsto be adhesively secured together where they overlap. However withconventional wrapping systems this requires the application of a liquidor flowable adhesive substance, e.g. a glue, to the edge zone of thewrapping material as this is unrolled by the wrapping machine and laidonto the exterior surface of the article being wrapped.

The provision of such gluing apparatus naturally increases the cost ofthe machine, but there is the additional disadvantage that supplies ofan appropriate adhesive are required to be maintained, and moreover theoperational difficulties in maintaining the gluing apparatus to functionproperly under conditions of use is such that such apparatus has not metwith commercial success.

The use of wrapping materials, coated with conventional adhesivematerials of the kind which are tacky and adhere to most materials whichare not specially treated has not generally been considered to bepracticable because of the need for a release paper or the like betweenadjacent turns of the material in the roll on which it is supplied, andthe adherance of contaminating material to any exposed area of saidadhesive material on the wrapping material when in use, or the adherenceof the wrapping material to the articles wrapped therein.

One proposal which attempts at least partially to overcome suchdrawbacks is described in U.S. Pat. No. 4,409,776. This involves using awrapping material which has an adhesive coating on one face only andforming two layers of wrapping around the article, an inner layer inwhich the adhesive-coated face is presented outwardly and an outer layerin which the adhesive-coated face is presented inwardly. In this way, noadhesive material contacts the wrapped article, nor it is exposedexternally. However, this method has several disadvantages. Inparticular, since two layers of wrapping are required, it uses twice thequantity of wrapping material which would be required by a single-layerwrapping technique. Specifically, in this proposal the second layer isformed by reversing the wrapping machine so that it is suitable only forbatch operation rather than continuous wrapping. Alternatively, to adaptthe method for continuous wrapping, it would be necessary to provide twowrapping machines, one for each layer, with consequent increase incapital and maintenance costs as well as extra space requirements.

The object of the invention is to provide an improved method of wrappingelongate articles which obviates or reduces the above-mentioneddisadvantages.

SUMMARY OF THE INVENTION

According to the invention we provide a method of wrapping an elongatearticle by forming a winding of at least one strip of flexible wrappingmaterial helically around said article so that successive turns of thewrapping overlap one another, characterised by the use of a strip ofwrapping material wherein a first face of the strip carries first andsecond portions of a coating of an adhesive substance of a per se knownkind which without the application of heat adheres strongly only toitself and wherein a second face of the strip is free from said adhesivematerial, and by the steps of turning over a longitudinal edge portionof said strip which includes said first portion of the coating so as tofold the second face of the strip onto itself, and laying the foldedstrip onto the article with the second portion of the coating on eachturn of the winding in contact with the first portion of said coating onan adjacent turn of the winding.

Since the adhesive substance is formulated not to adhere to the uncoatedsurface of the strip of wrapping material, it can be formed into a rollwithout necessitating the use of release paper. It can also be handledby wrapping machinery without difficulty, and it will not adheredirectly to the article being wrapped. However, as the wrapping materialis fed towards the article to be wrapped, with the coated facepreferably presented away from the article, one edge portion is foldedunder so as to bring the first portion of the coating beneath theuncoated face and in face-to-face relation with the second portion ofthe coating on the previous turn of wrapping material. Thus, the firstand second portions of the adhesive coating are brought into contactwhere adjacent turns overlap, so as to form a strong bond.

The adhesive material used is preferably of the kind generally known asa "cold seal" adhesive. Conveniently the adhesive may be applieduniformly across the entire width of the first face of the wrappingmaterial, so that the first and second portions of the coating arecontinguous and the degree of overlap between adjacent turns of thewinding can be varied in different applications. However, in some casesthe first and second portions of the adhesive coating may be spacedapart, for example confined to the opposite marginal regions of thefirst face. This may be particularly desirable where the wrappingmaterial is relatively wide so as to avoid wastage of adhesive in thecentral region where adhesion is not likely to be required.

Typically the wrapping material may be in the form of a strip having awidth of between about 5 cms and about 15 cms. The material may comprisea suitable grade of paper, reinforced if necessary, single ormultiple-ply, creped or plain. Other materials such as plastic films,metal foils or non-woven web materials may also be used whereappropriate.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention will now be described by way of example with reference tothe accompanying drawings wherein:

FIG. 1 shows apparatus for carrying out the method of the invention

FIG. 2 shows in more detail a preferred arrangement for turning over aportion of the wrapping material; and

FIG. 3 is a schematic section through part of a wrapped articlecomprising a bundle of individual elements.

DETAILED DESCRIPTION OF A PREFERRED EMBODIMENT

In a generally conventional manner elongate elements A are assembledinto bundles B which are held together, for example by means of rollers(not shown) and advanced through a wrapping station in the directionindicated by arrow C, although some form of primary fastener such asself-adhesive tape, plastic or metal strapping may be necessary to holdtogether a bundle comprising of a substantial number of elongateelements with complex cross-sectional configurations. In the wrappingstation, a roll 10 of wrapping material 12 is mounted on a roller holder21 carried by an annular member 20 which surrounds the bundle B androtates in the direction of arrow D as the bundle B advances through thewrapping station. Material 12 from the roll 10 is thus wrapped aroundthe bundle B to form a helical winding 50 in which adjacent turns 50a,50b, 50c etc. of the wrapping material overlap.

In accordance with the invention, the wrapping material comprises astrip with one face 13 (preferably the face which is presented away fromarticles A) having a coating of "cold seal" adhesive material, forexample of the kind comprising a blend of natural and synthetic rubberswhich has only a low tack with regard to other materials, but bondssecurely with itself without the application of heat.

In the illustrated embodiment, the face 13 is coated over its entirewidth and the opposite face 15 is uncoated. However, for the purposes ofthe invention, the adhesive coating can be considered to be dividednotionally into two portions, namely a first portion 13a adjacent to oneedge 12a of the material and a second portion 13b remote from said edge12a. Nevertheless, the coating need not necessarily extend across theentire width of the face 13, and the two portions need not becontiguous. Thus, the first portion may be disposed at or adjacent tothe edge 12a of the material and the second portion may be disposed ator adjacent to the opposite edge 12b.

In the roll 10, the coated face 13 of the material is presentedoutwardly and as the material is dispensed from the roll it passesthrough a tension controlling arrangement comprising pins 22, 24 and atension roller 23 carried by the annular member 20. Thereafter, thematerial passes through a folding device 30 comprising a mounting plate30a carrying a first pin 31, a flat plate 32 and a guide assembly 33including spaced U-shaped members 34, 36 and an intermediate J-shapedmember 35, all embracing the flat plate 32 and in combination with theplate defining the path of the material 12 towards the bundle B. Thefirst pin 31 has a length somewhat less than the width of the material12 so as to allow the margin adjacent to edge 12a to fold over the endof the pin. The members 34, 35 and 36 extend from the plate 30a and eachis successively shorter. The rounded end portion 34a of the first member34 ensures that the margin of the material is turned downwardly and theninwardly, and the succeeding members 35, 36 complete the folding of thematerial so as to bring the first portion 13a of the coated face 13beneath the plate 32 so that as the material leaves the folding devicethe first portion 13a of the coated face is disposed beneath the secondor remaining portion 13b. The folded material then passes around twofurther tensioning pins 37, 38 before being applied to the bundle B.

Thus, the inturned marginal portion 13a of the coated face of each turn(such as 50d) of wrapping as it is laid down is presented towards theremaining portion 13b of the coated face of the previous turn (such as50c) of wrapping material on the bundle B, thereby causing adjacentturns to adhere firmly to one another under the tension applied by thewrapping process.

Because of the nature of the adhesive material employed, the wrappingmachine does not require any special maintenance and there is no releasepaper or the like to be discarded. The adjacent turns of the wrappingare securely adhered together so as to prevent the ingress of dirt ormoisture. The turned over edge of the wrapping material is moreresistant to mechanical damage than the exposed edge of unfoldedwrapping materials as previously employed, and when the bundle is to beunwrapped the wrapping can simply be slit along the length of the bundleand be removed in a single piece or a few pieces instead of falling intomany fragments as is the case when conventional wrappings are employed.

Preferably, the adhesive material is applied across the full width ofthe wrapping material, and is applied to the bundle B with the uncoatedface in contact with the articles A. However, other arrangements arepossible. In particular, where convenient two or more separate stripsmay be applied simultaneously from respective rolls carried at spacedpositions around the annular member 30. The adhesive coated face mayalternatively be presented towards the bundle B, with the marginalportion turned outwardly instead of inwardly. Also, in some cases theadhesive material may be applied only to the lateral marginal portionsof the wrapping material, instead of across the full width. The coatedportions need not extend fully to the edges of the material. Thus, withwrapping material having a width of for example approximately 15 to 20cms, the adhesive material may be confined to areas approximately 5 cmswide along each edge, allowing for an overlap of up to 5 cms on adjacentturns. However, where the wrapping material is somewhat narrower,typically between about 5 cms and about 10 cms, it is convenient to coatthe full width of the material as this enables the width of the turnedover margin and the width of the overlap to be varied to suit differentapplications, without requiring wrapping material specific for suchapplications.

In order to ensure that adjacent turns of the wrapping material areadequately secured to one another, the wrapping machine many includerollers (not shown) downstream of the wrapping station to engage theexterior surface of the bundle and press the turns of wrapping materialtogether.

It is also particularly advantageous to make use of wrapping material inthe form of crepe paper, applied in such a manner that the paper issomewhat stretched as it is applied to the bundle B, the tension in thepaper also serving to hold successive turns together. Additionally, theinherent elasticity of crepe paper enables the wrapping to stretch asnecessary if the bundle B bends during subsequent handling andtransportation.

Whilst in the accompanying drawings the bundle B is shown to be composedof several straight articles A, it will be appreciated that the articlesmay be of curved or other non-linear form and the bundle may be ofeither constant or varying cross-sectional dimensions through-out itslength, subject only to the ability of the bundle to pass through theannular member 20. The bundle may also be in the form of a loop, forexample a coil of wire, but in such a case the annular member will inknown manner be formed as two separable components which can be partedto allow insertion and removal of the bundle.

Of course, as previously mentioned, the method may also be applied tosingle articles as well as to bundles of articles.

We claim:
 1. A method of wrapping an elongate article by forming awinding of at least one strip of flexible wrapping material helicallyaround said article so that successive turns of the wrapping overlap oneanother, characterized by the use of a strip of wrapping materialwherein a first face of the strip carries first and second portions of acoating of an adhesive substance of a per se known kind which withoutthe application of heat adheres strongly only to itself and wherein asecond face of the strip is free from said adhesive material, and by thesteps of turning over a longitudinal edge portion of said strip whichincludes said first portion of the coating so as to fold the second faceof the strip onto itself, and laying the folded strip onto the articlewith the second portion of the coating on each turn of the winding incontact with the first portion of said coating on an adjacent turn ofthe winding while said second portion of said coating on said first faceof the strip is directed away from the article being wrapped and saidlongitudinal edge portion is turned inwardly, said first portion of thecoating facing towards the article being wrapped.
 2. A method accordingto claim 1 wherein said first and second portions of the adhesivecoating are contiguous.
 3. A method according to claim 2 wherein saidadhesive coating extends across substantially the entire width of saidfirst face.
 4. A method according to claim 1 wherein said first andsecond portions of the adhesive coating are spaced apart across thewidth of said strip.
 5. A method according to claim 1 wherein saidadhesive substance is substantially nonadherent to said second face ofsaid strip.
 6. A method according to claim 5 wherein said adhesivesubstance is substantially nonadherent to the article being wrapped. 7.A method according to claim 1 wherein said adhesive substance issubstantially nonadherent to the article being wrapped.
 8. A method ofwrapping an elongate article by forming a winding of at least one stripof flexible wrapping material helically around said article so thatsuccessive turns of the wrapping overlap one another, characterized bythe use of a strip of wrapping material wherein a first face of thestrip carries first and second portions of a coating of an adhesivesubstance of a per se known kind which without the application of heatadheres strongly only to itself and wherein a second face of the stripis free from said adhesive material, and wherein said adhesive substanceis substantially non-adherent to said second face of said strip andsubstantially non-adherent to the article being wrapped, and by thesteps of turning over a longitudinal edge portion of said strip whichincludes said first portion of the coating so as to fold the second faceof the strip onto itself, and laying the folded strip onto the articlewith the second portion of said coating on each turn of the winding incontact with the first portion of said coating on an adjacent turn ofthe winding.
 9. A method of wrapping an elongate article by forming awinding of at least one strip of flexible wrapping material helicallyaround said article so that successive turns of the wrapping overlap oneanother, characterized by the use of a strip of wrapping materialwherein a first face of the strip carries first and second portions of acoating of an adhesive substance of a per se known kind which withoutthe application of heat adheres strongly only to itself and wherein asecond face of the strip is free from said adhesive material, andwherein said adhesive substance is substantially non-adherent to thearticle being wrapped, and by the steps of turning over a longitudinaledge portion of said strip which includes said first portion of thecoating so as to fold the second face of the strip onto itself, andlaying the folded strip onto the article with the second portion of thecoating on each turn of the winding in contact with the first portion ofsaid coating on an adjacent turn of the winding.